Behavioural Processes

Objective and efficient methods for investigating animal's mental states are important for advancing animal welfare research. Behavioural observations and physiological measures provide valuable information but may not fully capture affective states. Judgment Bias Tasks (JBTs) offer a promising method to infer affective states from animals' responses to ambiguous stimuli, as distressed individuals show more pessimistic tendencies. However, the application of JBTs outside research settings may be limited due to time-consuming training and methodological or infrastructural requirements. With the present study, we aimed to test the feasibility of a simple and accessible JBT for non-human primates and to investigate its sensitivity to affective states. Eight brown capuchins (Sapajus apella) and eleven Tonkean macaques (Macaca tonkeana) were tested under positive and negative affective conditions. Individuals were trained to discriminate between never rewarded conditioned stimuli and always rewarded ones. They were then presented with ambiguous probes they had never seen before to analyse their responses to ambiguity. The discrimination training required, on average, about 12 sessions lasting a few minutes each to successfully train every individual animal. Both species significantly discriminated between conditioned stimuli and ambiguous probes. Additionally, macaques showed a greater tendency to interact with the never rewarded condition stimuli and the probes under positive conditions during early sessions. In capuchins, however, the affective conditions presented had no significant effect, although the descriptive analysis tended to show that the latency to investigate the probes was greater in the negative condition. This study also highlights key methodological considerations, such as a decrease in ambiguity across sessions. Overall, the present results suggest that, with a few improvements, this method could be effectively implemented to assess affective states of primates under human care, supporting this tool as a valuable candidate for welfare assessment.

Courtship is an essential component of reproductive success for many species and many courtship behaviors, such as vocalization, are energetically demanding. In order to successfully balance investment in courtship with feeding and foraging, individuals must be aware of their current energy balance, and hormonal signals of energetic state have been found to influence social signal effort across a variety of species. Ghrelin is one hormone that plays an important role in regulating energy balance by signaling hunger and promoting feeding. Previous studies have investigated the role of ghrelin in courtship, aggression, and mating behavior. In this study, we build on prior work by investigating the effects of ghrelin on ultrasonic vocalizations (USV) and other courtship behaviors of male mice. We expand on previous research by observing ghrelin's effects over longer interactions, allowing us to understand how ghrelin impacts the dynamics of USV production over time. Our results show that while males initially vocally court females at a high rate regardless of treatment, ghrelin reduces overall USV production by increasing the rate of decline of vocalization. Surprisingly, despite its effects on vocal courtship, we found no significant differences in the production or timing of other, non-vocal, courtship behaviors. This study deepens our understanding of the role of hormones traditionally associated with controlling hunger and feeding in regulating social behaviors.

Zoos and public aquariums serve as essential hubs for wildlife conservation, public education, and scientific research; however, the success of these missions depends upon maintaining high animal welfare standards despite constant human presence. A primary concern is the 'visitor effect': the alteration of animal behavior due to human presence. While this phenomenon is well-documented in captive mammals and has been explored in chondrichthyes, it remains largely unexamined in teleost fish, despite evidence of their sensitivity to human stimuli in natural environments. This study addresses this knowledge gap by investigating the behavioral responses of 13 teleost species to varying levels of crowd density, direct human solicitation, and ambient noise. Our multivariate analysis reveals that visitor density and visitor-induced disturbances are significant drivers of behavioral change, with species identity acting as the primary source of variance. We observed high inter-taxonomic variability: while several species (including Euxiphipops sextriatus, Dascyllus aruanus, and Zebrasoma flavescens) showed marked sensitivity through significant alterations in stress-coping, exploration, and aggression, others remained behaviorally stable. Furthermore, acoustic analysis indicates a complex soundscape where visitor density correlates with increased sound amplitude, particularly in the 100 Hz to 400 Hz range, a critical band for teleost hearing suggesting that visitor-induced noise is distinct from the aquarium's technical background noise. These findings underscore that the 'visitor effect' is not a uniform phenomenon but a complex interaction shaped by species-specific sensitivity and distinct anthropogenic stressors. Our results highlight the necessity of incorporating species-specific behavioral data and acoustic monitoring into welfare management protocols to better mitigate the impact of human presence on captive fish populations.

Ethanol occurs naturally in sugar-rich foods used by insects, but its effects in bees have been studied primarily in honeybees. We tested whether dietary ethanol affects survival and locomotor performance in workers of the bumblebee Bombus terrestris (L.). In the survival experiment, workers were fed ethanol (0, 1, or 10%) for 21 days; in the locomotor experiment, they were fed the same doses for one or seven days, after which we measured spontaneous movement using an open-field assay. We measured the proportion of time in movement, speed of movement, path meander (curviness), and arena exploration. The 10% ethanol concentration greatly increased the risk of mortality, whereas the estimated effect of 1% ethanol was smaller and statistically inconclusive. In terms of locomotion, the largest differences occurred after seven days of exposure to 10% ethanol. Workers in this treatment showed greater path meander and lower exploration than control workers. Speed was also lowest in this group. Evidence that exposure for seven days was worse than for one day at the same concentration was detected only for exploration. No clear locomotor effect was detected at 1% ethanol exposure. These findings provide comparative data on sustained ethanol exposure in bumblebees and show a strong concentration-dependent contrast, with substantial effects under high-concentration challenge but no clear effects on the measured endpoints at 1%.

Female-female competition is increasingly recognized as a key driver of female ornamentation, including birdsong, which often functions in intrasexual competition. However, the specific resources females use elaborate traits to compete for remain unclear. In addition, few studies have simultaneously investigated the use of multiple competitive traits in females, despite growing independent interest in these traits (e.g., female song and aggression). We investigated the competitive contexts of female song, aggression and calling behavior in northern house wrens (Troglodytes aedon) to determine which resources females compete for across the breeding season. We simulated conspecific territorial intrusions using female song at three breeding stages representing different contexts: arrival (mate and territory acquisition), nest building (nest site and breeding status defense), and egg laying (brood defense). We tested whether female song and physical aggression varied as reproductive resources shifted across the breeding cycle. Females were significantly more aggressive during nest building, showing 5.8 times greater odds of a higher-intensity aggressive response during nest building compared to arrival. Female song output was similar across early stages but declined during egg laying, though this was not statistically significant after correction for multiple comparisons and individuals varied substantially in overall singing propensity. Non-song vocalizations varied by call type and breeding stage. Calls associated with aggression occurred most frequently during nest building, consistent with peak physical aggression responses. Together, these results identify nest building as the stage of highest female aggression, consistent with heightened competition over nest cavities and associated breeding status in this cavity-nesting species. In contrast, female song occurred across all stages and appears to function in multiple competitive contexts. This study provides evidence for context and mode-specific female signaling in a temperate songbird and highlights that females strategically use aggression, calls, and song to mediate social conflict across breeding contexts.

Reliable morphological criteria for sexing birds without the need for invasive procedures are scientifically and ethically valuable. Smith et al (2005) reported that iris colour assigns the genetic sex of Starlings Sturnus vulgaris with 98% accuracy, and bill base colour with 100% accuracy when birds are in breeding condition, but these figures have not been tested independently. We applied their criteria to 31 captive Starlings in breeding condition, using three observers blind to genetic sex, two of them new to Starling sexing. Bill base colour correctly predicted genetic sex for all 29 birds scored, with complete observer agreement. Mean iris score was correct for 27 of 31 (87.1%), fewer than the 94 of 96 reported by Smith et al (2005) for birds in breeding condition (Fisher exact test, P = 0.031), although with so few errors in either study this comparison is imprecise. Observer agreement was high, so these errors reflect iris colouration conflicting with genetic sex rather than inconsistent scoring; bill base colour was correct for all four misassigned birds. Body mass and tarsus length classified 77% and 58% of birds correctly, their published thresholds missing in opposite directions. We conclude that bill base colour should be the primary criterion for sexing Starlings in breeding condition; the accuracy of iris colour should not be assumed to be 98%.

It is estimated that approximately fifty percent of the population will encounter at least one traumatic event during their lifetime; however, only six percent develop Posttraumatic Stress Disorder (PTSD), a trauma-related disorder characterized by persistent alterations in affect and cognition, including an exaggerated fear response. It is well established that females (9.7%) are more than twice as likely as males (3.6%) to be diagnosed with PTSD. Nevertheless, a significant challenge remains in understanding how the severity of traumas experienced in childhood versus adulthood influences PTSD development across sexes. To address this challenge effectively, the adoption of preclinical animal models that accurately reflect these key characteristics is crucial. The Stress Enhanced Fear Learning (SEFL) paradigm in rodents encapsulates some of these complexities associated with PTSD, such as persistent fear sensitization following exposure to acute trauma. This study investigates how stress severity and developmental timing affect the long-term maintenance of SEFL in male and female rats. Juvenile and adult rats were initially subjected to no stress (control, context only), low stress (1 footshock), moderate stress (3 footshocks), or high stress (15 footshocks), followed by an extinction session either one day (recent) or sixty days (remote) later. Subsequently, to evaluate SEFL in a new context, all subjects received a single footshock and were tested the following day. Shortly after stress induction, all groups displayed SEFL. Although the effects persisted for sixty days in adult males and juvenile females, even at the lowest stress level, they were significantly reduced in juvenile males and adult females. These findings offer novel insights into sex-related differences in the persistence of SEFL and introduce new considerations regarding how the timing of developmental stressors influences future threat encoding and fear responses.

Background: ADHD is characterized by inattention and impulsivity. Stimulants such as amphetamine are the first line treatments for ADHD. Amphetamine (AMPH) works by increasing extracellular levels of dopamine and noradrenaline. Such stimulants are used to test predictive validity of animal tasks, where it has been reported that amphetamine improves rat 5-CSRTT accuracy when the session length is increased to 250 trials. This improvement in accuracy was observed later in the session as control performance declined. Proving that amphetamine can improve 5C-CPT task performance adds to the predictive validity of the task. No previous works has demonstrated the pro-attentional effects of amphetamine on sustained attention in rat 5C-CPT. We have previously shown that pharmacological manipulations of dopaminergic system improve waiting impulsivity in a rate dependent manner and the importance of analysing the data using Oldham method. The present study extends this work to investigate the effect of amphetamine on attentional processes. Objective: to investigate effects of amphetamine on attentional processes as measured by 5C-CPT task using correlational analysis and group performance. Methods: Trained female Lister hooded rats were tested with AMPH (0.1, 0.2 and 0.4 mg/kg) under reduced stimulus duration schedule (0.25,0.5,1,1.5 and 2s SD) over normal length session (120 trials). Correlational analysis (Oldham method) was used to understand the relationship between baseline performance measures and the change following administration of AMPH. Results: The highest dose of AMPH impaired attentional performance in the 5C-CPT under reduced SD challenge (0.5s,1s,1.5s and 2s). This impairment was due to increase in FAR. Previous studies in 5-CSRTT suggest that reducing the SD increases attentional demand in the form of reducing accuracy without affecting waiting impulsivity. However, the 5-CSRTT does not include non-target trials, therefore, it cannot be used to measure sustained attention (SI) and responsivity index. The 5C-CPT requires greater attentional resources than the 5-CSRTT.This study is the first to report that reducing the SD changes responsivity index (bias) rather than measures of sustained attention (sensitivity index) in the 5C-CPT. Control sensitivity index did not change until the SD was reduced to less than 0.5s and this change was due to a change in baseline responsivity index (bias). Performance under each reduced SD revealed that the highest dose of AMPH (0.4 mg/kg) showed a tendency toward reducing sensitivity index at 0.5, 1.0 and 1.5s SDs. Under 1.0s SD, the highest dose of AMPH changed sustained attention (SI, HR and FAR) and omission in a rate-dependent manner without changing responsivity index. Performance across the session revealed that the impairment in sustained attention was observed at the beginning of the session. In the third trial block, Oldham method revealed an inverse relationship between baseline accuracy and the change following administration of 0.2 mg/kg AMPH, indicative of a rate-dependent effect. Conclusions: This study successfully demonstrates rate-dependent effects of AMPH on measures of attentional performance in the 5C-CPT. This experiment also demonstrates that responsivity index is sensitive to reduced SD challenge. To our knowledge this is the first study to report the presence of a direct relationship between baseline sustained attention and magnitude of improvement following administration of 0.4 mg/kg AMPH and an inverse relationship between baseline accuracy and the change following administration of 0.2 mg/kg AMPH in 5C-CPT task. Future studies should test lower doses of amphetamine (0.05 and 0.1 mg/kg) over extended session length (250 trials) to reveal the pro-attentional effects of this drug on 5C-CPT performance measures.

Resource handling time is an important cost to foraging animals and this is especially true for low-ranking individuals who may be displaced before they acquire rewards. Handling may also require visual attention that can lead to a trade-off between scanning the environment and focusing on food acquisition. We ran a foraging experiment on wild vervet monkeys where we simultaneously offered them three puzzle boxes in a straight-line array that increased sequentially in handling difficulty and reward value. We found that differences in competitive ability had a large impact on access to long-handling time resources and willingness to invest time in costly problem-solving when social interference was possible. Resources with lower handling time and smaller rewards were accessed by individuals of all dominance ranks but only dominant monkeys that did not fear displacement attempted the high handling time puzzle box. Handling time improved with experience at each puzzle box and contrary to predictions, when vigilance rates were higher, monkeys were also faster at solving puzzle boxes. Thus, there is not necessarily a trade-off between attention to foraging tasks that require handling and vigilance, if a high scanning frequency to both can be balanced with limited scanning duration. These results have important implications for understanding the decision-making of foraging animals that live in competitive groups and the diets of individuals, which may vary with dominance when important resources require long handling times.

Stressors experienced during the postnatal period may increase vulnerability to mental health disorders, including postpartum depression and anxiety. In rodents, maternal separation (MS) has been shown to alter behaviours in dams, but these observations have been made almost exclusively in rats and thus robust mouse models of postpartum mental health disorders using this stressor remain limited. Here we first examined, in mice, the effects of MS on maternal caregiving and on anxiety- and depressive-like behaviours. As stress-induced inflammatory activation in the gut-brain axis has been associated with behavioural alterations in non-postpartum contexts, changes in pro-inflammatory cytokines and tight junction proteins in the brain and intestinal tract were also examined. Female C57BL/6N mice were assigned to a No Separation (NS) or a MS condition that consisted of 3-hour daily separation sessions from postnatal days (P) 2 to 14. Maternal care behaviours were assessed on P3 and P7, followed by anxiety- and depressive-like behaviours on P22 and P23, and the collection of the medial prefrontal cortex (mPFC) and colon on P24 to determine the expression of selected genes. Caregiving patterns in MS dams fluctuated throughout the early postnatal period. Although behaviours and gene expression outcomes remained unchanged by MS, grooming time in the splash test was correlated with the expression of different genes in the mPFC. These findings suggest that C57BL/6 mouse dams may be less sensitive to the actions of MS on behaviour and on brain and intestinal markers of inflammation and barrier permeability, at least when examined shortly after weaning.

Translocations are commonly used to reduce the risk of extinction of threatened species, and often to reintroduce animals to their former habitats. If extirpation occurred a long time ago, individuals may be placed into novel environments outside of conditions they have previously experienced, which can affect translocation success. To measure success of translocations, particularly those to novel habitats, it is important to monitor post-release spatial behaviour. In 2023, ten critically endangered k[a]k[a]p[o] (Strigops habroptilus) were released to form a new population at the fenced mainland island of Sanctuary Mountain Maungatautari (hereafter Maungatautari) in the North Island of New Zealand, an area from which they were extirpated approximately a century earlier. The spatial behaviour and habitat selection of these k[a]k[a]p[o] was analysed using dynamic space use and step selection functions with temporally dynamic responses applied to GPS logger data recorded over a seven month period. These showed three unexpected results: k[a]k[a]p[o] were highly mobile and used larger areas compared to other sites; there was synchronicity of movement, with most individuals simultaneously moving toward the perimeter fence in spring; and when near the fence k[a]k[a]p[o] selected for areas of pasture and exotic vegetation more than anticipated. While direct comparisons are difficult due to varying data availability, this unexpected spatial behaviour and habitat selection suggests that k[a]k[a]p[o] behavioural responses were different at Maungatautari compared to other sites. This may indicate that k[a]k[a]p[o] released at Maungatautari had a longer exploratory stage than elsewhere; that there were behavioural effects influenced by conspecific density or the availability of novel and exotic vegetation; or that there were specific breeding habitat requirements not met at the site during the study period. These results highlight the importance of high-resolution spatial monitoring to evaluate the success of translocations, particularly those to novel environments.

The study of animal personality has gained increasing attention in recent years, as researchers recognize that non-human animals exhibit stable individual differences in behaviour. In dairy cattle, understanding personality traits holds potential for improving animal welfare, enhancing management practices, and supporting productivity outcomes. However, validating the behavioural tests used to assess these traits remains a significant challenge. The present study aimed to evaluate the consistency and validity of five commonly used behavioural tests in dairy cows: the Human Approach Test (HAT), Sudden Test (SUD), Novel Object Test (NOT), Open Field Test (OFT), and Novel Surface Test (NST). These tests were chosen for their potential to assess personality dimensions that parallel components of human personality, particularly Openness, Neuroticism, Extraversion, and Agreeableness. Repeated assessments were conducted across three time periods to evaluate both intra-test (temporal) and inter-test (contextual) consistency. Results revealed that only the SUD exhibited significant behavioural consistency across all periods, suggesting its potential as a reliable tool for personality assessment. Additionally, a moderate correlation between the HAT and SUD was observed, indicating that these tests may capture overlapping personality traits. In contrast, the remaining tests (NOT, OFT, NST) lacked consistent behavioural patterns over time and across contexts, raising questions about their reliability and the complexity of trait expression. These findings highlight the challenges of identifying stable personality traits in cattle and emphasize the need for more rigorous validation of behavioural tests. This research contributes to the growing field of animal personality by providing insights into trait stability, the limitations of current testing methods, and the potential application of personality assessment in future livestock management practices.

Categorical rhythmic patterns are fundamental features found in language and music across cultures. In humans, these rhythmic patterns occur in both vocal production and perceptual preference, highlighting a link between rhythmic production and preference. Categorical rhythmic patterns have recently been identified in animal vocalisations too, but whether rhythm production is linked with rhythmic preferences in non-human animals remains unclear. Within this context, zebra finches (Taeniopygia castanotis) are of particular interest, as both sexes develop a song preference, and their song has been suggested to exhibit an isochronous temporal structure. Here, we tested for the first time whether zebra finches prefer songs containing discrete rhythmic patterns, using operant preference tests with either two or four rhythmic patterns. Our results show that no categorical rhythmic pattern was consistently preferred across the population, although responses varied among individuals. These findings indicate that categorical rhythmic patterns are unlikely to be a primary driver of song preference in zebra finches. Together with previous work in other vocal-learning birds, our results suggest that preferences for categorical rhythmic patterns may not be universal and could instead reflect species-specific features of vocal displays rather than the rhythmic categories characteristic of human music.

Background Opioid-free anaesthesia (OFA) has emerged as an alternative to opioid-based anaesthesia (OBA), but its benefit over OBA for postoperative quality of recovery (QoR) remains unclear. To address this question while limiting variability inherent in clinical studies, such as analgesic regimens and patient psychosocial factors, we investigated the effects of OFA versus OBA on postoperative recovery in a controlled preclinical mouse model. Methods Adult male and female C57BL/6J mice underwent laparotomy or sham procedures under isoflurane anaesthesia, and were randomly assigned to saline (control), fentanyl (OBA), or dexmedetomidine (OFA) as intraoperative analgesic adjuncts. All mice received multimodal postoperative analgesia, including carprofen. We adapted a standardised multidimensional recovery model using six behavioural endpoints reflecting human QoR domains: body weight, food intake, locomotor activity, mechanical sensitivity, sucrose preference, and social interaction. These endpoints were assessed on postoperative days 1, 2, 3, and 7. Plasma inflammatory cytokine and brain-derived neurotrophic factor (BDNF) concentrations were also measured in parallel as potential biological correlates of recovery. Results Over the study period, we observed no treatment effect across behavioural endpoints in laparotomised mice, including body weight (P=0.157), food intake (P=0.884), locomotor activity (P=0.864), mechanical sensitivity (P=0.628), sucrose preference (P=0.615), and social interaction (P=0.442). Composite QoR scores did not differ between OFA and OBA groups (P=0.569), with no differences in postoperative circulating inflammatory cytokine or BDNF concentrations. Conclusions Dexmedetomidine-based OFA and fentanyl-based OBA produced similar postoperative behavioural recovery, circulating inflammatory cytokine and BDNF trajectories in laparotomised mice receiving multimodal postoperative analgesia.

Semi-occluded vocal tract (SOVT) exercises are widely used in voice training and therapy, but their immediate electroglottographic (EGG) effects remain incompletely characterized. In this pilot methodological study, six female community singers completed a no-straw baseline recording and then 1-min straw-phonation exercises with four straws (Household metal, Metal VoiceStraw, plastic, and paper), each followed by a no-straw EGG recording. Thirty 1s recordings were analyzed with a standardized pipeline including contact quotient (CQ), waveform skewness, contact-phase rise/fall timing, temporal skewness (s_t), a normalized derivative asymmetry index (NDAI), average-cycle morphology, and EGG spectral descriptors. Relative to baseline, group-mean CQ was higher after all four straws (by 0.027-0.058), waveform skewness and NDAI were lower, and the EGG spectral centroid was lower (by 9.6-15.3%). Contact-phase timing asymmetry did not change consistently: s_t exceeded baseline after three straws and fell below it after one, and the rise/fall ratio decreased in three to five of six participants depending on the straw. Four participants ranked the Metal VoiceStraw first and two ranked paper first. Because every straw condition followed the baseline, warm-up and order effects cannot be separated from straw effects. These hypothesis-generating results identify CQ, waveform skewness, and EGG spectral centroid as candidate endpoints for a larger controlled study

Musical aesthetic experience can reveal students' cognitive, aesthetic, and emotional responses to music. However, how professional vocal training alters brain functions in female college students with varying levels of musicianship to promote these is unknown. Here we applied fMRI, psychological measures and Goldsmiths musical sophistication index (Gold-MSI) assessments to study 27 non-music major female college students consisting of instrument group (normal pitch accuracy with instrumental training), general group (normal pitch accuracy without instrumental training) and poor-pitch group (poor pitch accuracy and without instrumental training). After 1 year of one-on-one instructional practice, we found that professional vocal training enhanced information processing related to musical cognition and pleasure during musical aesthetic experiences across all three groups, involving improvements in motor control of vocalization, auditory feedback processing, musical memory and attention together with musical pleasure. Specifically, instrument group showed activation of reward circuits, general group exhibited activation of laryngeal motor control circuits, and poor-pitch group displayed activation of sensory/sensorimotor/motor control circuits. Both pre- and post-training, the instrument group exhibited higher connectivity than the other two groups in the left amygdala-dorsal anterior cingulate cortex (dACC) and the right posterior superior temporal gyrus (pSTG)-left insula pathway. After professional vocal training, the general group showed higher connectivity in the left amygdala-dACC, whereas the poor-pitch group demonstrated increased connectivity in the right pSTG-left insula and dACC-nucleus accumbens pathways. Surprisingly, professional vocal training activated the bed nucleus of the stria terminalis (BNST), a subcortical emotion center, and connectivity with the medial prefrontal cortex associated with musical information processing. Thus, vocal training can significantly improve musical cognition and aesthetic pleasure, and facilitates neural modulation in the brain's emotional centers.

Social animals must identify, evaluate, and appropriately respond to other individuals, often relying on multiple sources of information to guide context-dependent behavior. While individual recognition is thought to be widespread and critical for many social interactions (e.g. territoriality, dominance hierarchies), convincing demonstrations across animals beyond class-level recognition remain rare. Further, the cues animals use to recognize individuals remains poorly understood, especially in natural environments where they are exposed to numerous cues which may require cue integration. Here, we examine how socially dominant males of the African cichlid fish, Astatotilapia burtoni, use individual recognition to modulate aggression and whether this process depends on the spatial context. Using naturalistic experimental setups, we exposed males to familiar and unfamiliar neighbors while systematically manipulating spatial location and presenting a neighbor either singly or simultaneously to simulate competing social cues. Additionally, we measured circulating testosterone to assess endocrine correlates of recognition and aggression. We found that focal males habituated to familiar neighbors only when they remained in a consistent territorial location, demonstrating that spatial context is important for recognition. Further, when familiar and unfamiliar neighbors were presented simultaneously, males preferentially aggressed toward unfamiliar rival and adjust their aggressive response to the perceived threat of their neighbors, indicating that identity-based threat assessment is maintained under competing social demands. Together, our results show that recognition is a flexible, multi-faceted process that depends on the integration of identity and contextual information to guide territorial decision-making under dynamic social conditions.

Music is a central component of psychedelic settings, yet little experimental work has examined how psilocybin and musical composition influence music-evoked emotional responses in healthy volunteers. This exploratory, double-blind, placebo-controlled study assessed these effects during the plateau phase of psilocybin and the corresponding time window in placebo sessions following oral administration of psilocybin (0.26 mg/kg) or placebo. The study consisted of two parts. In Part 1 (n = 19), a pilot stage, the first half of participants rated music-induced affective valence for eight compositions representing different genres/subgenres (Rock/Punk, Metal/Industrial Metal, Metal/Industrial Metal, Classical/Baroque, Electronic/Dub, Folk/Nordic Folk, Electronic/Techno, Electronic/Trance, Electronic/Psytrance) using a visual analogue scale (VAS). Based on Part 1, the classical composition with the highest overall affective valence and the psytrance composition with the largest psilocybin-placebo contrast (i.e., the composition most responsive to psilocybin) were selected for Part 2 (n = 17), in which the second half of participants assessed emotional responses to music using the Geneva Emotional Music Scale (GEMS-9). Psilocybin increased wonder, transcendence, and joyful activation across both contrasting compositions. Relative to each other, the classical composition elicited greater peacefulness, tenderness, and nostalgia, whereas the psytrance composition elicited greater tension across both psilocybin and placebo conditions. A composition x condition interaction was observed for sadness: under psilocybin, sadness increased during the classical composition and decreased during the psytrance composition. These findings suggest that psilocybin and contrasting musical compositions independently influence different aspects of music-evoked emotional responses, with limited interaction effects, and point to potential implications for protocol design and music selection in psychedelic settings.

Foraging and feeding are often associated with vocalisations across animal species. Food calls may function to claim ownership of resources or recruit others to feeding sites, yet their potential role in facilitating food sharing remains poorly understood. This study investigates the relationship between food calls and food-sharing behaviour in common marmosets (Callithrix jacchus), focusing on adult-infant interactions, where food transfers are most frequent. We analysed over 1000 food interactions across six groups, categorising events as non-sharing (without begging or despite begging) or sharing (proactive, resisted, or facilitated). We examined the spectro-temporal structure of food calls produced immediately before each interaction. Food transfers were more likely to occur when preceded by a food call, suggesting a functional link between food calls and sharing. Random forest models reliably classified food calls according to interaction type, while generalized linear mixed models identified acoustic variation associated with sharing outcomes. Our results suggest that food calls encode information to either encourage or deter conspecific (infant) approach, influencing food transfer outcomes. These findings highlight the role of food calls in modulating social interactions around food in marmosets, advancing our understanding of vocal communication and its integration with cooperative behaviours in primates.

1. Organisms rely on environmental cues, such as moonlight illumination and weather, to modulate nocturnal behaviors that reduce predation risk and conserve energy during demanding periods. Urbanization can alter the reliability of cues, potentially impairing organisms' ability to respond appropriately with consequences in increasingly urbanized landscapes. 2. We leveraged the Motus Wildlife Tracking System to identify roost initiation, roost departure and nocturnal restlessness of dark-eyed juncos (Junco hyemalis) overwintering along an urban to rural gradient to determine if activity patterns are affected by weather, moonlight illumination, and urbanization. 3. Nocturnal behavior of overwintering juncos varied with environmental factors, including moonlight illumination and temperature. However, the strength of these responses differed among sites, suggesting that natural cues of moonlight illumination were masked in urban areas, where individuals were more responsive to temperature. 4. Our results suggest that urbanization weakens birds' responsiveness to natural light cues, likely because artificial lighting reduces the visibility of moonlight; representing a key mechanism by which human-altered landscapes can disrupt nocturnal ecology in birds.